Corrupted three

Three dead gods who found the pools of chaos, bi-product when creating elixir, and wanted to surprise the others with new creatures. They created the darkhalls to hide their work until ready. Diving into the pools, unaware of the effects of grim imbalance, they then attempted to make their own humans, but instead created the demons. Never expecting them to rebel, the three were consumed, and the death of the rest of their kind soon followed.